阅读说明：本技术 永磁同步电机交直轴电感快速估算方法及系统 (Method and system for rapidly estimating quadrature-axis and direct-axis inductance of permanent magnet synchronous motor ) 是由 顾明磊 程诚 李昭明 许心一 罗建武 于 2021-08-17 设计创作，主要内容包括：本发明公开了一种永磁同步电机交直轴电感快速估算方法,包括：输出永磁同步电机逆变器的一个空间电压矢量,将其施加到三相绕组,并持续一定时间,在结束时刻采集三相响应电流；一次采集完成后,等待三相响应电流归零,然后按照相同的方式施加其他2-5个空间电压矢量,并采集相应的三相响应电流；根据采集的三相响应电流计算永磁同步电机α、β轴下的电流i-(α),i-(β)；根据施加的空间电压矢量计算永磁同步电机α、β轴下的电压,并计算各电压时间积分；根据电流i-(α),i-(β)及各电压时间积分,计算永磁同步电机α、β轴下的电感矩阵；根据α、β轴下的电感矩阵计算永磁同步电机交、直轴的电感。本发明可在不增加硬件成本的情况下,快速进行d轴和q轴电感的估算。(The invention discloses a method for quickly estimating the quadrature-direct axis inductance of a permanent magnet synchronous motor, which comprises the following steps: outputting a space voltage vector of the permanent magnet synchronous motor inverter, applying the space voltage vector to the three-phase winding for a certain time, and collecting three-phase response current at the end time; after one-time collection is finished, waiting for the three-phase response current to return to zero, and applying the three-phase response current in the same wayAdding other 2-5 space voltage vectors, and collecting corresponding three-phase response current; calculating the current i under the alpha and beta axes of the permanent magnet synchronous motor according to the collected three-phase response current α ,i β (ii) a Calculating voltages under the alpha axis and the beta axis of the permanent magnet synchronous motor according to the applied space voltage vector, and calculating time integral of each voltage; according to current i α ,i β Time integration of all voltages is carried out, and inductance matrixes under alpha and beta axes of the permanent magnet synchronous motor are calculated; and calculating the inductances of the orthogonal and the direct axes of the permanent magnet synchronous motor according to the inductance matrixes under the alpha and beta axes. The invention can quickly estimate the d-axis and q-axis inductances without increasing the hardware cost.)

1. A method for quickly estimating the quadrature-direct axis inductance of a permanent magnet synchronous motor is characterized by comprising the following steps:

outputting a space voltage vector of the permanent magnet synchronous motor inverter, applying the space voltage vector to the three-phase winding for a certain time, and collecting three-phase response current at the end time;

after the primary collection is finished, waiting for the three-phase response current to return to zero, then applying other 2-5 space voltage vectors in the same way, and collecting the corresponding three-phase response current;

calculating the current i under the alpha and beta axes of the permanent magnet synchronous motor according to the collected three-phase response current_α,i_β；

Calculating voltages under the alpha axis and the beta axis of the permanent magnet synchronous motor according to the applied space voltage vector, and calculating time integral of each voltage;

according to current i_α,i_βTime integration of all voltages is carried out, and inductance matrixes under alpha and beta axes of the permanent magnet synchronous motor are calculated;

and calculating the inductances of the orthogonal and the direct axes of the permanent magnet synchronous motor according to the inductance matrixes under the alpha and beta axes.

2. The method of claim 1, wherein the three-phase current i is used for fast estimation of the quadrature-direct axis inductance of the PMSM_u，i_v，i_wAlpha and beta shaft lower current i of permanent magnet synchronous motor_α,i_βThe transformation relationship is as follows:

3. the method of claim 1, wherein the magnitude relationship between six space voltage vectors and each voltage of the permanent magnet synchronous motor under α and β axes is:

wherein V_dcIs the voltage of the dc capacitor of the inverter.

4. The fast estimation method of the quadrature-direct axis inductance of the PMSM according to claim 1, wherein the inductance matrix L is_αβ：

t₁-t₆Output duration for six space voltage vectors;is a 2 x 2 inductance matrix; i.e. i_αk,i_βkIs the current vector v under the alpha and beta axes of the permanent magnet synchronous motor_αk,v_βkThe corresponding value of the non-applied space voltage vector is set to 0 for the voltage vectors under the alpha and beta axes of the permanent magnet synchronous motor.

5. The method of claim 4, wherein an inductance matrix L under α and β axes is used to estimate the quadrature-axis and direct-axis inductances of the PMSM rapidly_αβAnd calculating the inductance L of the alternating and direct axes of the permanent magnet synchronous motor_d、L_q：

6. The method of claim 1, wherein the spatial voltage vectors are applied in any order and for the same time.

7. The method of claim 1, wherein the order of applying the space voltage vectors is arbitrary, and if the application time is different, equivalent current response with equal application time is derived by conversion.

8. A permanent magnet synchronous motor quadrature-direct axis inductance rapid estimation system is characterized by comprising:

the space voltage vector application module is used for respectively applying a plurality of space voltage vectors output by the permanent magnet synchronous motor inverter to the three-phase winding and lasting for a certain time;

the acquisition module is used for acquiring corresponding three-phase response current at the moment when each space voltage vector application is finished; after the acquisition is finished, waiting for the three-phase response current to return to zero;

a calculation module for calculating the current i under the alpha and beta axes of the permanent magnet synchronous motor according to the collected three-phase response current_α,i_β(ii) a Calculating voltages under the alpha axis and the beta axis of the permanent magnet synchronous motor according to the applied space voltage vector, and calculating time integral of each voltage; according to current i_α,i_βTime integration of all voltages is carried out, and inductance matrixes under alpha and beta axes of the permanent magnet synchronous motor are calculated; and calculating the inductances of the orthogonal and the direct axes of the permanent magnet synchronous motor according to the inductance matrixes under the alpha and beta axes.

9. The system for rapidly estimating quadrature-direct axis inductance of a permanent magnet synchronous motor according to claim 8, wherein the spatial voltage vector application module applies the plurality of spatial voltage vectors in an arbitrary order and at the same time.

10. The system of claim 8, wherein the space voltage vector application module applies a plurality of space voltage vectors in an arbitrary order, and if the application time is different, the equivalent current response when the application time is equal is derived by conversion.

Technical Field

The invention relates to a permanent magnet synchronous motor, in particular to a method and a system for quickly estimating the quadrature-axis and direct-axis inductance of the permanent magnet synchronous motor.

Background

Permanent magnet synchronous motors have been widely used in various industries due to their high efficiency, high power density, and the like. Quadrature axis inductance (also called d-axis inductance, Ld) and direct axis inductance (also called q-axis inductance, Lq) of a permanent magnet synchronous motor are important motor parameters in a motor control system. The dq-axis inductance needs to be accurately estimated on the problems of current loop control parameter design, motor temperature rise estimation, magnetic field saturation estimation, high-speed control, torque ripple control and the like.

At present, the method for measuring the dq axis inductance parameter of the permanent magnet synchronous motor mainly comprises three types:

(1) using LCR tester

The method needs to disconnect the connection between the motor and the inverter, connect the LCR equipment to the motor terminal, and repeatedly measure the inductance value corresponding to 0-360 degrees for many times to calculate the dq-axis inductance.

(2) High frequency pulsed voltage injection

The method needs to inject high-frequency pulse voltage continuously, and extracts current response through a low-pass filter to calculate the dq-axis inductance. The calculation process is long and generates continuous noise.

(3) Rotary electromotive force

The method needs the continuous and stable rotation of the motor, obtains a motor rotating electromotive force signal, calculates the motor flux linkage and further calculates the dq axis inductance. The method can not be used when the motor is in a static state.

It can be seen that the conventional dq-axis inductance measurement method either requires an additional tester, or requires a separate motor and inverter assembly, or cannot operate in a stationary state, or has a long calculation time, or has high frequency noise.

Disclosure of Invention

The invention mainly aims to provide an estimation method for d-axis and q-axis inductances, which can realize rapid calculation process, low noise and high precision.

The technical scheme adopted by the invention is as follows:

the method for quickly estimating the quadrature-direct axis inductance of the permanent magnet synchronous motor comprises the following steps:

outputting a space voltage vector of the permanent magnet synchronous motor inverter, applying the space voltage vector to the three-phase winding for a certain time, and collecting three-phase response current at the end time;

after the primary collection is finished, waiting for the three-phase response current to return to zero, then applying other 2-5 space voltage vectors in the same way, and collecting the corresponding three-phase response current;

calculating the current i under the alpha and beta axes of the permanent magnet synchronous motor according to the collected three-phase response current_α,i_β；

Calculating voltages under the alpha axis and the beta axis of the permanent magnet synchronous motor according to the applied space voltage vector, and calculating time integral of each voltage;

according to current i_α,i_βTime integration of all voltages is carried out, and inductance matrixes under alpha and beta axes of the permanent magnet synchronous motor are calculated;

and calculating the inductances of the orthogonal and the direct axes of the permanent magnet synchronous motor according to the inductance matrixes under the alpha and beta axes.

In connection with the technical scheme, the three-phase current i_u，i_v，i_wAlpha and beta shaft lower current i of permanent magnet synchronous motor_α,i_βThe transformation relationship is as follows:

according to the technical scheme, the magnitude relation between the six space voltage vectors and the voltages of the permanent magnet synchronous motor under the alpha and beta axes is as follows:

wherein V_dcIs the voltage of the dc capacitor of the inverter.

In connection with the above technical solution, the inductance matrix L_αβ：

t₁-t₆Output duration for six space voltage vectors;is a 2 x 2 inductance matrix; i.e. i_αk,i_βkIs the current vector v under the alpha and beta axes of the permanent magnet synchronous motor_αk,v_βkThe corresponding value of the non-applied space voltage vector is set to 0 for the voltage vectors under the alpha and beta axes of the permanent magnet synchronous motor.

According to the technical scheme, an inductance matrix L under alpha and beta axes is utilized_αβAnd calculating the inductance L of the alternating and direct axes of the permanent magnet synchronous motor_d、L_q：

In the above-described embodiment, the order of applying the plurality of space voltage vectors is arbitrary, and the application time is the same.

In the above-described embodiment, the order of applying the plurality of space voltage vectors is arbitrary, and if the application time is different, the equivalent current response when the application time is equal is derived by conversion.

The invention also provides a system for rapidly estimating the quadrature-axis and direct-axis inductance of the permanent magnet synchronous motor, which comprises:

the space voltage vector application module is used for respectively applying a plurality of space voltage vectors output by the permanent magnet synchronous motor inverter to the three-phase winding and lasting for a certain time;

the acquisition module is used for acquiring corresponding three-phase response current at the moment when each space voltage vector application is finished; after the acquisition is finished, waiting for the three-phase response current to return to zero;

a calculation module for calculating the current i under the alpha and beta axes of the permanent magnet synchronous motor according to the collected three-phase response current_α,i_β(ii) a Calculating voltages under the alpha axis and the beta axis of the permanent magnet synchronous motor according to the applied space voltage vector, and calculating time integral of each voltage; according to current i_α,i_βTime integration of all voltages is carried out, and inductance matrixes under alpha and beta axes of the permanent magnet synchronous motor are calculated; and calculating the inductances of the orthogonal and the direct axes of the permanent magnet synchronous motor according to the inductance matrixes under the alpha and beta axes.

In the above-described embodiment, the order of the plurality of space voltage vectors applied by the space voltage vector application module is arbitrary, and the application time is the same.

In the above-described embodiment, the order of the plurality of space voltage vectors applied by the space voltage vector application module is arbitrary, and if the application times are different, equivalent current responses when the application times are equal are derived by conversion.

The invention has the following beneficial effects: the invention applies a plurality of space vector voltages to the three-phase winding of the motor to respectively obtain corresponding current responses, and the d-axis and q-axis inductances of the motor are quickly estimated by using the voltage and current signals. The invention does not need an additional tester, does not need to separate the motor and the inverter assembly, and does not increase the hardware cost. The method has the advantages of quick calculation process, low noise and high precision in estimation of the d-axis inductance and the q-axis inductance.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic illustration of the d and q axis definitions of the present invention;

FIG. 2 is a schematic diagram of a permanent magnet synchronous motor inverter according to an embodiment of the present invention;

FIG. 3 is a flow chart of a method for fast estimation of quadrature-axis and direct-axis inductances of a permanent magnet synchronous motor according to an embodiment of the present invention;

FIG. 4 is a flow chart of a method for fast estimation of quadrature-axis and direct-axis inductances of a permanent magnet synchronous motor according to another embodiment of the present invention;

fig. 5 is a schematic diagram of a voltage-current inductance waveform according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Abbreviations and key term definitions in the present invention:

intersecting axes: also called d-axis, as shown in fig. 1, the d-axis is defined as the N-pole direction of the rotor magnetic pole of the permanent magnet synchronous motor.

A straight shaft: also called q-axis, as shown in fig. 1, the q-axis is defined as the direction of the positive d-axis rotating 90 ° counterclockwise.

α -axis: as shown in fig. 1, the α axis is defined in the 0 ° direction.

The beta axis: as shown in fig. 1, the β axis is defined in the 90 ° direction.

Quadrature axis inductance: also known as d-axis inductance, Ld.

Direct axis inductance: also known as q-axis inductor, L_q。

α -axis inductance: also known as d-axis inductance, L_α。

Beta-axis inductance: also known as q-axis inductor, L_β。

α -axis voltage: v_α。

β -axis voltage: v_β。

α -axis current: i.e. i_α。

Beta axis current: i.e. i_β。

d-axis voltage: v_d。

q-axis voltage: v_q。

d-axis current: i.e. i_d。

q-axis current: i.e. i_q。

LCR: and (4) inductance-capacitance resistance.

Fig. 2 is a schematic diagram of a permanent magnet synchronous motor inverter according to an embodiment of the present invention, and the definitions of space voltage vectors generated by the on-off combinations of the 6 switches Q1-Q6 of the inverter are shown in table 1. And C is an inverter direct-current capacitor, and the voltage of the inverter direct-current capacitor is Vdc.

TABLE 1 space Voltage vector V₁～V₆Defining, switching states of a universal three-phase inverter

Space voltage vector

V1

V2

V3

V4

V5

V6

Opening of

Q1Q6Q2

Q4Q3Q2

Q1Q3Q2

Q4Q6Q5

Q1Q6Q5

Q4Q3Q5

Switch off

Q4Q3Q5

Q1Q6Q5

Q4Q6Q5

Q1Q3Q2

Q4Q3Q2

Q1Q6Q2

Example 1:

as shown in fig. 3, the method for quickly estimating the quadrature-axis and direct-axis inductances of the permanent magnet synchronous motor in the embodiment mainly includes the following steps:

s1, outputting a space voltage vector of the permanent magnet synchronous motor inverter, applying the space voltage vector to the three-phase winding for a certain time, and collecting three-phase response current at the end time;

s2, after one-time collection is completed, waiting for the three-phase response current to return to zero, then applying other 2-5 space voltage vectors according to the same mode, and collecting corresponding three-phase response current;

s3, calculating the current i under the alpha and beta axes of the permanent magnet synchronous motor according to the collected three-phase response current_α,i_β；

S4, calculating voltages under the alpha and beta axes of the permanent magnet synchronous motor according to the applied space voltage vector, and calculating time integral of each voltage;

s5, according to the current i_α,i_βTime integration of all voltages is carried out, and inductance matrixes under alpha and beta axes of the permanent magnet synchronous motor are calculated;

and S6, calculating the inductances of the orthogonal and the direct axes of the permanent magnet synchronous motor according to the inductance matrixes under the alpha and beta axes.

Specifically, 6 space vector voltages are applied to the three-phase windings of the motor, and corresponding three-phase current responses are collected. Space voltage vector V₁～V₆In the method, three-phase current responses are generated after each space voltage vector is applied to a three-phase winding of the motor, and the three-phase current responses i are collected at the moment when each space voltage vector is applied_u1～i_u6,i_v1～i_v6,i_w1～i_w6. The expression of the three-phase current response in an alpha and beta coordinate system is i_α1～i_α6,i_β1～i_β6。

In principle, each space voltage vector application time t₁～t₆Are the same value. Since the equivalent current response when the application times are equal can be derived by conversion in the calculation even if the application times of the space voltage vectors are different, the application times t of the space voltage vectors are different₁～t₆May be set to different values.

Example 2:

the embodiment takes a salient pole permanent magnet synchronous motor as an example, and space voltage vectors V are sequentially applied₁、V₆、V₂、V₅、V₄、V₃The estimation method of the d-axis and q-axis inductances is shown in fig. 4, and specifically includes the following steps:

step 101: output space voltage vector V₁Applied to the three-phase winding for a time t₁；

Step 102: space voltage vector V₁Collecting three-phase response current i at the moment of application ending_u1，i_v1，i_w1；

Step 103: no space voltage vector is output, and the three-phase response current is waited to return to zero;

step 201: output space voltage vector V₆Applied to the three-phase winding for a time t₆；

Step 202: space voltage vector V₆Collecting three-phase response current i at the moment of application ending_u6，i_v6，i_w6；

Step 203: no space voltage vector is output, and the three-phase response current is waited to return to zero;

step 301: output space voltage vector V₂Applied to the three-phase winding for a time t₂；

Step 302: space voltage vector V₂Collecting three-phase response current i at the moment of application ending_u2，i_v2，i_w2；

Step 303: no space voltage vector is output, and the three-phase response current is waited to return to zero;

step 401: output space voltage vector V₅Applied to the three-phase winding for a time t₅；

Step 402: space voltage vector V₅Collecting three-phase response current i at the moment of application ending_u5，i_v5，i_w5；

Step 403: no space voltage vector is output, and the three-phase response current is waited to return to zero;

step 501: output space voltage vector V₄Applied to the three-phase winding for a time t₄；

Step 502: space voltage vector V₄Collecting three-phase response current i at the moment of application ending_u4，i_v4，i_w4；

Step 503: no space voltage vector is output, and the three-phase response current is waited to return to zero;

step 601: output space voltage vector V₃Applied to the three-phase winding for a time t₃；

Step 602: space voltage vector V₃Collecting three-phase response current i at the moment of application ending_u3，i_v3，i_w3；

Step 603: no space voltage vector is output, and the three-phase response current is waited to return to zero;

step 701: calculating the time integral v of each voltage under the alpha and beta axes_α1t₁～v_α6t₆,v_β1t₁～v_β6t₆；

Step 702: calculating the current response i under the alpha and beta axes_α1～i_α6,i_β1～i_β6；

Step 703: calculating d and q axis inductance L_d,L_q。

Wherein, Table 2 shows the space voltage vector V_1-V₆Decomposed to voltage v under alpha and beta axes_α1-6,v_β1-6The magnitude relationship of (1). V_dcIs the voltage of the dc capacitor of the inverter.

TABLE 2 relationship between space voltage vector and voltages on α and β axes

A schematic diagram of the voltage current inductance waveform of the present invention is shown in fig. 5. Each space voltage vector V₁～V₆Acting for a corresponding time t₁～t₆. At t_1-t₆Collecting the response current i at the end time of_α1～i_α6,i_β1～i_β6. D-axis inductance L and q-axis inductance L are calculated through the calculation method_d,L_q。

Three-phase current i_u，i_v，i_wAnd alpha, beta axis down current i_α,i_βThe transformation relationship of (1):

where k ∈ {1,2,3,4,5,6 }.

Using voltage v under alpha and beta axes_α1-6,v_β1-6Time of voltage application t₁～t₆Current i_α1-6,i_β1-6Calculating inductance matrix L under alpha and beta axes_αβ：

Using inductance matrices L under the alpha, beta axes_αβCalculating d and q axis inductances L_d,L_q。

Example 3:

compared with embodiment 2, this embodiment changes the number and the application order of the space voltage vectors. This example successively combines V₁、V₂、V₄Or V₃、V₅、V₆Three space voltage vectors are applied to the three phase windings of the motor. Each space voltage vector is applied for a time t₁～t₃. And applying the space voltage vectors in any order to obtain corresponding three-phase current response. In the above formula, the unused voltage/current signal may be set to 0.

Example 4:

compared with embodiment 3, this embodiment changes the number and the application order of the space voltage vectors. This example uses V in sequence₁、V₃、V₄、V₆Or V₂、V₃、V₄、V₅Or V₁、V₂、V₅、V₆Four space voltage vectors are applied to the three phase windings of the motor. Each space voltage vector is applied for a time t₁～t₄. The order of application of the space voltage vectors is arbitrary. And obtaining corresponding three-phase current response. In the above formula, the unused voltage/current signal may be set to 0.

In order to implement the method of the above embodiment, the present invention further provides a system for rapidly estimating a quadrature-direct axis inductance of a permanent magnet synchronous motor, including:

the space voltage vector application module is used for respectively applying a plurality of space voltage vectors output by the permanent magnet synchronous motor inverter to the three-phase winding and lasting for a certain time;

the acquisition module is used for acquiring corresponding three-phase response current at the moment when each space voltage vector application is finished; after the acquisition is finished, waiting for the three-phase response current to return to zero;

a calculation module for calculating the current i under the alpha and beta axes of the permanent magnet synchronous motor according to the collected three-phase response current_α,i_β(ii) a Calculating voltages under the alpha axis and the beta axis of the permanent magnet synchronous motor according to the applied space voltage vector, and calculating time integral of each voltage; according to current i_α,i_βTime integration of all voltages is carried out, and inductance matrixes under alpha and beta axes of the permanent magnet synchronous motor are calculated; and calculating the inductances of the orthogonal and the direct axes of the permanent magnet synchronous motor according to the inductance matrixes under the alpha and beta axes.

Further, the order of the plurality of space voltage vectors applied by the space voltage vector application module is arbitrary, and the application time is the same.

Further, the order of the plurality of space voltage vectors applied by the space voltage vector application module is arbitrary, and if the application time is different, equivalent current responses when the application time is equal are derived by conversion.

All the modules of the system are for implementing the above method functions, and the above method processes may be directly referred to, and specific functions are not described herein.

In conclusion, the invention provides a method for estimating d-axis and q-axis inductances of a permanent magnet synchronous motor. In a static state, a plurality of space vector voltages are applied to three-phase windings of the motor, corresponding current responses are obtained respectively, and d-axis and q-axis inductances of the motor are quickly estimated by using the voltage and current signals. The invention does not need an additional tester, does not need to separate the motor and the inverter assembly, and does not increase the hardware cost. The method has the advantages of quick calculation process, low noise and high precision in estimation of the d-axis inductance and the q-axis inductance.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.